2005 Volume 46 Issue 4 Pages 812-819
As a fundamental study of slags in metallurgical processes, liquidus lines in the FeO(wüstite)–CaO–SiO2 and Fe3O4(spinel)–CaO–SiO2 systems were determined at temperatures between 1573 and 1673 K and partial pressures of oxygen between 10−4 and 36 Pa using a quenching method with a crucible of platinum foil. It was found that the two phases (solid wüstite and liquid) region in the FeO–CaO–SiO2 system (1573 K) increased remarkably by changing the partial pressure of oxygen from 10−4 to 10−3 Pa. It was also found that the two phases (solid spinel and liquid) region in the Fe3O4–CaO–SiO2 system (1573 K) at PO2 of 10−2 Pa was a little larger than that in the FeO–CaO–SiO2 system at PO2 of 10−3 Pa but it was extended considerably when the oxygen pressure was increased to 10−1 Pa. However, the two liquids region did no change too much in the range of oxygen pressure above 10−1 Pa even though the liquidus line became almost parallel to the Fe3O4–CaO axis in the ternary diagram when the oxygen pressure was increased. Furthermore, it was found that the two phase region in the Fe3O4–CaO–SiO2 system at PO2 of 10−1 Pa decreased remarkably with increasing temperature. On the basis of the obtained and reported data, the homogeneous liquid regions in the FeOX–CaO–SiO2 systems (1573 K) at PO2 of 10−3 Pa, 10−1 Pa and in air were compared.